We develop a theory of optimal estate taxation in a model where bequest inequality is driven by differences in parental altruism. We show that a wide range of results are possible, from positive taxes to subsidies. The results depend on redistributive objectives implicit in the cardinal specification of utility and social welfare functions. We propose a normalization that is helpful in classifying these different possibilities. We isolate cases where the optimal policy bans negative bequests and taxes positive bequests, features present in most advanced countries.